Methods and kits for locking and disinfecting implanted catheters

ABSTRACT

Implanted catheters are locked with a solution comprising a lower alcohol, typically ethanol, propanol, or butanol, in a range from 1% to 99% by volume, and an additive in a range from 1% to 99% by volume, the additive comprising an anti-microbial, typically taurolidine or triclosan, or an anti-coagulant, typically riboflavin, sodium citrate, ethylene diamine tetraacetic acid, or citric acid. The use of an alcohol and additive solution can effectively reduce fouling of the catheter, particularly clotting and thrombus in intravascular catheters, as well as eradicate existing infections and/or reduce the risk of potential infections. Existing infections and/or potential infections can be further reduced by employing a catheter body which permits an anti-microbial solution to penetrate into the catheter body and preferably through the catheter into tissue surrounding the implanted catheter.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application is a continuation-in-part of, and claims the benefit ofpriority from, U.S. patent application Ser. No. 09/611,421, filed Jul.7, 2000, which was a continuation-in-part of U.S. patent applicationSer. No. 09/359,842, filed Jul. 23, 1999, now U.S. Pat. No. 6,592,564the full disclosures of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to medical methods and kits.More particularly, the present invention relates to methods and kits forflushing an interior lumen of an implanted catheter prior to closing thecatheter between successive uses.

Implanted catheters enjoy widespread use in a number of medicalprocedures. For example, intravenous (IV) therapy relies on long-termimplantation of a venous catheter to deliver fluids, medications, andother substances to a patient. Hemodialysis and hemofiltration both relyon separate draw and return catheters implanted in a vein to allow extracorporeal treatment of the blood. Peritoneal dialysis, in contrast,relies on a single catheter implanted in the peritoneum to permitintroduction and withdrawal of dialysate to permit in situ dialysis.

The need to leave catheters implanted over long periods of time raises anumber of concerns. For example, the catheters can become infectedrequiring treatment of the patient and often times removal of thecatheter. This is a particular problem with transcutaneous catheterswhere the skin penetration is a common route of infection. Secondly,implanted catheters can often become plugged or fouled over time. Thisis a particular problem with intravascular catheters where clotting andthrombus formation within the catheter lumen can be problematic.

To reduce problems associated with thrombus formation, it is now commonto “lock” intravascular access catheters between successive uses.Locking typically involves first flushing the catheter with saline toremove blood and other substances from the catheter lumen. After thecatheter has been flushed, an anti-coagulant solution, typicallyheparin, is then injected to displace the saline and fill the lumen. Theheparin-locking solution both excludes blood from the lumen and activelyinhibits clotting and thrombus formation within the lumen. While somethrombus may still form at the distal tip of the catheter, the formationis usually minimal and presents few problems. It has further beenproposed to combine various anti-microbial substances with the lockingsolution in order to inhibit infection at the same time that thrombus isbeing inhibited.

While generally effective, the use of heparin locks suffers from anumber of disadvantages. The need to prepare a heparin solution at theend of every catheter treatment session is time-consuming and presentsan opportunity for error by a caregiver. Hemodialysis and hemofiltrationpatients will have to undergo such heparin locks at least several timesa week, while patients on IV may have to undergo such heparin locksseveral times a day. Over time, the inconvenience and expense ofperforming heparin locks can build up. Moreover, the need to combine aseparate anti-microbial agent in the heparin lock solution furthercomplicates the procedure and adds expense, and the addition of ananti-microbial agent to the heparin lock will generally be effectiveonly within the lumen and at the openings from the lumen. There will belittle reduction in the risk of infection in the regions surrounding theimplanted catheter, including at the point of penetration through theskin where the risk of infection is the greatest.

For all these reasons, it would be desirable to provide improvedmethods, compositions, and kits for locking implanted catheters betweensuccessive uses. Such locking methods should inhibit fouling of thecatheter lumens and eradicate existing infections and/or reduce thechance of potential infections. In particular, such methods,compositions, and kits should be easy to implement, require minimum orno preparation, be of low cost, and be useful with most or all types ofimplanted catheters, including hemodialysis and hemofiltrationcatheters, IV catheters, peritoneal dialysis catheters, and the like. Atleast some of these objectives will met by the inventions describedhereinafter.

2. Description of the Background Art

U.S. Pat. No. 4,929,242 describes a solution containing glycerol andhaving a density similar to that of blood for providing a heparin lockon an intravenous catheter. U.S. Pat. No. 5,077,281 describes ananti-microbial solution containing a taurolin compound for inhibitingcoagulation in dialysis catheters and other vascular prostheses. PCT WO00/01391 describes an anti-microbial lock comprising a taurinamidederivative. Commonly assigned U.S. Pat. Nos. 5,807,356; 5,931,829;5,989,239; 5,997,524; 6,007,5165; 6,120,492; 6,132,415; and 6,193,684;and co-pending patent application Ser. Nos. 09/003,772; and 09/161,044,are relevant to the present application. All of the above patents andpending applications are incorporated herein by reference.

SUMMARY OF THE INVENTION

The present invention provides methods and kits for the improved lockingand/or disinfection of subcutaneously and transcutaneously implantedcatheters. The catheters typically will have a distal end which is opento a body lumen. Most commonly, the catheters will be intravascularcatheters where the distal end is implanted in or attached to a bloodvessel, usually a vein, but in some cases an artery. Exemplaryintravascular catheters include hemodialysis and hemofiltrationcatheters, intravenous catheters, and the like. Intravenous catheterscan be used for a wide variety of purposes, including fluid infusion,drug delivery, and the like. Catheters attached other than to thevasculature include peritoneal dialysis catheters which are open to theperitoneal cavity, and the like.

The catheters which are treated by the methods of the present inventionmay be transcutaneously implanted or subcutaneously implanted. By“transcutaneously implanted,” it is meant that the distal end of thecatheter is attached to or implanted within a target body lumen and aproximal end of the catheter is located externally to the patient. Anintermediate portion of the catheter will thus pass through or penetratethe patient's skin, and the proximal end of the catheter will usuallyhave a hub to permit selective attachment of infusion tubes, syringes,solution bags, and the like. Most commonly, the proximal attachment hubwill have a luer fitting. By “subcutaneously implanted,” it is meantthat the entire catheter is implanted beneath the skin and no portion ofthe catheter extends through the skin. Such subcutaneously implantedcatheters are typically attached to a fully implanted hub at theirproximal ends. The hub permits percutaneous access via a needle or otherpenetrating element. After a treatment session is finished, the needleor other penetrating element is removed and all portions of the catheterand proximal hub are then located beneath the skin. Examples of suchsubcutaneously implanted catheters and proximal access hubs aredescribed in the commonly assigned, copending applications describedabove, as well as U.S. Pat. No. 5,807,356, the full disclosures of whichhave previously been incorporated herein by reference.

As described in the Background section above, both transcutaneously andsubcutaneously implanted catheters are subject to fouling and plugging,particularly in and about their distal ends which are implanted in orattached to a blood vessel or other body lumen. To reduce the risk ofsuch fouling, the present invention provides methods, compostions, andkits for filling a lumen of the implanted catheter with a solution of alower alcohol and an additive. The lower alcohol is typically ethanol,propanol, or butanol, with isopropanol being the preferred alcohol.Surprisingly, it has been found that these lower alcohols are effectivein inhibiting fouling and plugging of the lumen, particularly ininhibiting clot formation within the lumens of intravascular catheters.The ability to inhibit clot formation without the need to prepare anduse heparin solutions is a significant advantage. Moreover, the loweralcohols have the additional ability to eradicate existing infectionsand/or inhibit potential infections. The additive may comprise either ananti-microbial substance, typically taurolidine or triclosan, or ananti-coagulant substance, typically riboflavin, sodium citrate, ethylenediamine tetraacetic acid, or citric acid. This solution combination of alower alcohol and an additive is particularly effective since alcoholincreases the effectiveness of the anti-microbial or anti-coagulantadditives, while the additives in return reduce the possible toxiceffects of the alcohol. Thus, both the reduction of catheter fouling andthe eradication and/or inhibition of infection can be achieved with theuse of commonly available, widely accepted materials which areintroduced to the catheter lumen in a convenient fashion, as describedin more detail below.

The ability to eradicate existing infections and/or inhibit potentialinfections of the implanted catheter can be improved by utilizingcatheters where at least a portion of the catheter body permits thelower alcohol to permeate the catheter body and, preferably, passoutwardly into the tissue region surrounding the catheter. The catheterbody may be porous or substantially non-porous (i.e. still permitssufficient diffusion of the lower alcohol, typically from a distal tipof the catheter into the tissue region surrounding the tip). While theuse of such catheter bodies can be beneficial with many anti-microbiallocking solutions, such as that taught in U.S. Pat. No. 5,077,281, thefull disclosure of which has been incorporated herein by reference, itis particularly useful with the lower alcohols of the present invention.It will be appreciated that the lower alcohols have relatively lowmolecular weights and polar structures which will enable them to readilypenetrate into and optionally through many porous or partially porousmaterials. Exemplary porous materials for construction of the catheterbody include silicone rubber, expanded PTFE (e.g., GORE-TEX®, medicalmembranes) and the like. Such materials may be formed into the tubularcatheter bodies or may be incorporated as separate component(s) into thecatheter bodies.

In a first aspect, a locking composition for filling an implantablecatheter comprises at least one lower alcohol in a range from 1% to 99%by volume and at least one other anti-microbial or anti-coagulantcompound in a range from 1% to 99% by volume. The lower alcohol isselected from the group consisting of ethanol, propanol, and butanol,with the presently preferred alcohol being isopropanol. The loweralcohol will usually be in aqueous solution, typically at 1% to 99% byvolume, usually from 5% to 95% by volume. The at least one otheranti-microbial is selected from the group consisting of taurolidine andtriclosan, and the at least one anti-coagulant is selected from thegroup consisting of riboflavin, sodium citrate, ethylene diaminetetraacetic acid, and citric acid. The implantable catheter may be atranscutaneous catheter attached at its distal end to a body lumen,typically a blood vessel, the peritoneal cavity, or the like.Alternatively, the implantable catheter may be a subcutaneouslyimplantable catheter which is attached at its distal end to a bloodvessel, the peritoneal cavity, or the like. The locking composition maybe used with porous or substantially non-porous catheter bodies, asdescribed above.

In a second aspect, a locking composition comprises one lower alcohol ina range from 1% to 99% by volume and at least one other anti-microbialor anti-coagulant compound in a range from 1% to 99% by volume. Thelower alcohol is selected from the group consisting of ethanol,propanol, and butanol, with isopropanol being the preferred alcohol. Theat least one other anti-microbial is selected from the group consistingof taurolidine and triclosan, and the at least one anti-coagulant isselected from the group consisting of riboflavin, sodium citrate,ethylene diamine tetraacetic acid, and citric acid. A preferredconcentration of the anticoagulant is about 4% by volume. Mostpreferably, the concentration of the locking composition comprisesisopropanol by about 17.5% volume and sodium citrate by about 4% weightto volume.

In a third aspect, a method according to the present invention fordisinfecting an implanted catheter comprises introducing ananti-microbial solution into a lumen of the catheter, wherein at least aportion of the catheter permits sufficient diffusion of theanti-microbial solution outwardly from the lumen into the catheter body,and preferably into tissue surrounding the catheter to eradicate anexisting infection. Exemplary and preferred anti-microbial solutionsinclude at least one lower alcohol, preferably ethanol, propanol, orbutanol, and most preferably isopropanol. The solution may furthercomprise at least one other anti-microbial, preferably taurolidine ortriclosan, or anti-coagulant compound, preferably riboflavin, sodiumcitrate, ethylene diamine tetraacetic acid, or citric acid, as describedabove. The implanted catheters may be subcutaneously or transcutaneouslyimplanted.

In a forth aspect of the present invention, a kit for disinfecting animplantable catheter comprises a container (optionally a syringe)holding a volume of a solution of a lower alcohol and instructions foruse. The instructions set forth a method comprising introducing thesolution into a lumen of the catheter, wherein at least a portion of thecatheter permits sufficient diffusion of the solution outwardly from thelumen into the catheter body, and preferably into tissue surrounding thecatheter to eradicate an existing infection. The kit may furthercomprise a package for holding both the container and the instructionsfor use, such as a box, tray, tube, pouch, or the like. The loweralcohol is typically selected from the group consisting of ethanol,propanol, and butanol, with isopropanol being the preferred alcohol. Thevolume of the solution in the container is typically in the range from 1ml to 20 ml, preferably from 2 ml to 10 ml, usually being about 2 ml to4 ml. Additionally, the container will usually comprise a syringe topermit direct introduction of the solution into the implantablecatheter.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A and 1B illustrate methods according to the present inventionfor locking and disinfecting a transcutaneous catheter.

FIGS. 2A-2C illustrate methods according to the present invention forlocking and disinfecting a subcutaneously implanted catheter.

FIGS. 3A-3C illustrate methods according to the present invention forlocking and disinfecting a peritoneal dialysis catheter.

FIG. 4 illustrates a preferred aspect of the present invention where ananti-microbial locking fluid permeates into an implanted catheter bodyand preferably into the tissue surrounding the catheter body.

FIG. 5 illustrates a kit constructed in accordance with the principlesof the present invention.

DESCRIPTION OF THE SPECIFIC EMBODIMENTS

Referring now to FIGS. 1A and 1B, a method according to the presentinvention for locking a transcutaneously implanted venous catheter 10will be described. The venous catheter 10 will be implanted through apatient's skin S into a vein V for infusion of the patient. When it isdesired to disconnect the patient from the source of infusion, it willbe necessary to lock the catheter to inhibit plugging and fouling causedby coagulation, and preferably to further eradicate existing infectionand/or inhibit the risk of infection. Shown in FIG. 1A, a tube 12containing an IV solution will normally be connected to the proximal hub14 of the catheter 10. The IV line 12 will be disconnected, and thecatheter 10 usually flushed with saline or other flushing solution.After the flushing is completed, a solution of a lower alcohol and anadditive can be introduced to fill the inner lumen of the catheter 10,as shown in FIG. 1B. Usually, a sufficient volume of the solution (asset forth above) will be introduced to completely fill the lumen, withminimum excess passing from distal end 16 of the catheter. The loss ofexcess solution into a blood vessel or most other body lumens, however,will generally not be a problem. The “column” of the solution will thenoccupy the inner lumen, and the proximal hub 14 will be sealed, helpingretain the solution in place. It has been found that the solution of thelower alcohol with the additive will effectively inhibit clotting andcoagulation at the distal end 16 as well as to eradicate existinginfections and/or inhibit potential infections throughout the catheter.When it is desired to reattach the patient to the IV source, thesolution will be removed and the catheter lumen flushed with saline.

The locking composition for filling the implantable catheter typicallycomprises at least one lower alcohol and at least one otheranti-microbial or anti-coagulant compound. Preferred compositionsinclude lower alcohol in the range between about 1% to 99% withtaurolidine in the range between about 1% to 99%, lower alcohol in therange between about 1% to 99% with triclosan in the range between about1% to 99%, lower alcohol in the range between about 1% to 99% withriboflavin in the range between about 1% to 99%, lower alcohol in therange between about 1% to 99% with sodium citrate in the range betweenabout 1% to 99%, lower alcohol in the range between about 1% to 99% withethylene diamine tetraacetic acid in the range between about 1% to 99%,and lower alcohol in the range between about 1% to 99% with citric acidin the range between about 1% to 99%. Saline, water, or standard heparinsolution may also be added to any of the above described compositions.

Referring now FIGS. 2A-2C, locking of a subcutaneously implantedcatheter 20 used for hemodialysis access will be described. The catheter20 is implanted between a target blood vessel BV, typically a vein, andan implanted port 22. During hemodialysis, blood may be withdrawnthrough the catheter 20, through the port 22 and externally through aneedle N and connecting line 23 used to percutaneously access the port22. Alternatively, the port and catheter could be used to return treatedblood to the patient. As described in the copending applicationsincorporated by reference above, the port and catheter combinations aretypically used in pairs to permit both blood withdrawal and bloodreturn.

When it is desired to end a hemodialysis (or hemofiltration) treatment,saline will be introduced through the needle N (typically from a syringewhich is attached to the connecting line 23) to flush the lumen, asshown in FIG. 2B. After the flush is complete, a container such assyringe 26 containing the solution of the lower alcohol with an additiveis injected through the port 22/line 23 and into the lumen of catheter20 to displace the saline and lock the catheter. The solution willremain in place within the catheter 20 after the needle end is withdrawnand the valve 22 closed to seal off the proximal end of the catheter 20.As a particular advantage, residual solution in the needle will bedispersed in the tissue tract TT left by the needle as well as inportions of the port 22 upstream of its internal valve. The presence ofthe alcohol or other anti-microbial additives in the solution willfurther eradicate existing infections and/or inhibit potentialinfections in both the port and tissue tract.

The methods of the present invention may also be used to locknon-vascular catheters, such as peritoneal dialysis catheters 30, asshown in FIGS. 3A-3C. After a peritoneal dialysis treatment, the useddialysate will be withdrawn from the catheter 30, as shown in FIG. 3A.After the dialysate has been sufficiently removed, the dialysis catheter30 may optionally be flushed with saline, as shown in FIG. 3B. Afterflushing, the solution of the lower alcohol with the additive isintroduced to the peritoneal dialysis catheter 30, as shown in FIG. 3C,so that it fills the lumen of the catheter, as described previously withthe vascular catheters. The use of an alcohol lock with an additive forperitoneal dialysis catheters is particularly advantageous ineradicating existing infections and/or inhibiting potential infections.

Referring now to FIG. 4, the use of lower alcohols for disinfecting acatheter can be enhanced by utilizing an implanted catheter where atleast a portion of the catheter body permits the lower alcohol topermeate the catheter body. When the lumen 40 of the catheter body 42 isfilled with a solution of a lower alcohol, the solution will be able topenetrate into the catheter body and preferably outwardly into thetissue T surrounding the catheter, as shown by the arrows in FIG. 4. Asdescribed above, the catheter body may be porous or substantiallynon-porous (i.e. still permits sufficient diffusion of the lower alcoholinto the tissue region typically surrounding a distal tip of thecatheter). Thus, the anti-microbial properties of the solution will notbe limited to the interior lumen of the catheter, but will also beeffective on a surface or distal tip of the catheter and in the tissueregion immediately surrounding the catheter body to eradicate existinginfections and/or inhibit potential infections. Particularly suitableporosity properties for the catheter bodies have been set forth above.The solution may further incorporate any of the anti-microbial oranti-coagulant compounds described above.

Referring now to FIG. 5, kits according to the present invention willcomprise at least a container 60, such as a syringe, for holding avolume of the solution of the lower alcohol. The volume will typicallybe within the ranges set forth above. In addition, the kit will containinstructions for use (IFU) setting forth a method for disinfecting animplanted catheter by introducing the solution into a lumen of thecatheter, wherein at least a portion of the catheter permits sufficientdiffusion of the solution outwardly from the lumen into the catheterbody, and preferably into tissue surrounding the catheter to eradicatean existing infection. Usually, the kits will further contain a package62, such as any conventional medical device package, including boxes,tubes, trays, pouches and the like.

While the above is a complete description of the preferred embodimentsof the invention, various alternatives, modifications, and equivalentsmay be used. Therefore, the above description should not be taken aslimiting the scope of the invention which is defined by the appendedclaims.

What is claimed is:
 1. An implantable catheter filled with a lockingcomposition, the locking composition comprising: at least one loweralcohol in a range from 1% to 99% by volume; and at least one otheranti-microbial compound or at least one anti-coagulant compound in arange from 1% to 99% by volume.
 2. An implantable catheter as in claim1, wherein the lower alcohol is selected from the group consisting ofethanol, propanol, and butanol.
 3. An implantable catheter as in claim2, wherein the lower alcobol is isopropanol.
 4. An implantable catheteras in claim 1, wherein the at least one other anti-microbial compound isselected from the group consisting of taurolidine and triclosan.
 5. Animplantable catheter as in claim 1, wherein the at least oneanti-coagulant compound is selected from the group consisting ofriboflavin, sodium citrate, ethylene diamine tetraacetic acid, andcitric acid.
 6. An implantable catheter as in claim 5, wherein the atleast one anti-coagulant compound is riboflavin at about 4% by volume.7. An implantable catheter as in claim 5, wherein the at least oneanti-coagulant compound is sodium citrate at about 4% by volume.
 8. Animplantable catheter as in claim 5, wherein the at least oneanti-coagulant compound is ethylene diamine tetraacetic acid at about 4%by volume.
 9. An implantable catheter as in claim 5, wherein the atleast one anti-coagulant compound is citric acid at about 4% by volume.10. An implantable catheter as in claim 1, wherein the implantablecatheter is a subcutaneous catheter implantable between a subcutaneousport and a body lumen.
 11. An implantable catheter as in claim 10,wherein the catheter is open to blood flow in a blood vessel.
 12. Animplantable catheter as in claim 10, wherein the catheter is open to aperitoneal cavity.
 13. An implantable catheter as in claim 10, whereinthe locking composition is introducible with a needle that disperses thecomposition in the port and tissue tract leading to the port as theneedle is withdrawn from the port.
 14. A locking composition comprising:at least one lower alcohol in a range from 1% to 99% by volume, whereinthe lower alcohol is isopropanol; and at least one anti-coagulantcompound in a range from 1% to 99% by volume, wherein the anti-coagulantcompound is sodium citrate or citric acid.
 15. A composition as in claim14, wherein the at least one anti-coagulant compound is sodium citrateat about 4% by volume.
 16. A composition as in claim 14, wherein the atleast one anti-coagulant compound is citric acid at about 4% by volume.17. A locking composition comprising: at least one lower alcohol in arange from 1% to 99% by volume; and at least one anti-coagulant compoundin a range from 1% to 99% by volume, wherein the at least oneanti-coagulant compound is riboflavin.
 18. A composition as in claim 17,wherein the at least one anti-coagulant compound is riboflavin at about4% by volume.
 19. A locking composition comprising: at least one loweralcohol in a range from 1% to 99% by volume; and at least one otheranti-microbial compound in a range from 1% to 99% by volume, wherein theat least one other anti-microbial compound is taurolidine.
 20. Acomposition as in claim 19 or 17, wherein the lower alcohol is selectedfrom the group consisting of ethanol, propanol, and butanol.
 21. Acomposition as in claim 20, wherein the lower alcohol is isopropanol.22. A method for disinfecting an implanted catheter, said methodcomprising: introducing an anti-microbial solution to a lumen of thecatheter, wherein at least a portion of the catheter permits sufficientdiffusion of the anti-microbial solution outwardly from the lumen into(issue surrounding the catheter to eradicate an existing infection, theanti-microbial solution comprising at least one lower alcohol and atleast one other anti-microbial compound or at least one anti-coagulantcompound in a range from 1% to 99% by volume.
 23. A method as in claim22, wherein the lower alcohol is selected from the group consisting ofethanol, propanol, and butanol.
 24. A method as in claim 23, wherein thelower alcohol is isopropanol.
 25. A method as in claim 22, wherein theother antimicrobial compound is selected from the group consisting oftaurolidine and triclosan.
 26. A method as in claim 22, wherein the atleast one anti-coagulant compound is selected from the group consistingof riboflavin, sodium citrate, ethylene diamine tetraacetic acid, andcitric acid.
 27. A kit for disinfecting an implantable catheter, saidkit comprising: a container holding a volume of a solution comprising alower alcohol and at least one other anti-microbial compound or at leastone anti-coagulant compound in a range from 1% to 99% by volume; andinstructions for use setting forth a method comprising introducing thesolution to a lumen of the catheter, wherein at least a portion of thecatheter permits sufficient diffusion of the solution outwardly form thelumen into tissue surrounding the catheter to eradicate an existinginfection.
 28. An implantable catheter as in claim 1, wherein theimplantable catheter is a transcutaneous catheter open to a body lumen.29. An implantable catheter as in claim 28, wherein the catheter is opento blood flow in a blood vessel.
 30. An implantable catheter as in claim28, wherein the catheter is open to a peritoneal cavity.
 31. A kit as inclaim 27, wherein the volume is in the range from 1 ml to 20 ml.
 32. Akit as in claim 27, wherein the container comprises a syringe.
 33. Animplantable catheter filled with a locking composition, the lockingcomposition comprising: at least one lower alcohol in a range from 1% to99% by volume; and at least one additive in a range from 1% to 99% byvolume; wherein the implantable catheter is a transcutaneous catheteropen to a body lumen.
 34. An implantable catheter filled with a lockingcomposition, the locking composition comprising: at least one loweralcohol in a range from 1% to 99% by volume; and at least one additivein a range from 1% to 99% by volume; wherein the implantable catheter isa subcutaneous catheter implantable between a subcutaneous port and abody lumen.